Molders station sand screen



Jan. 20, 1953 R. MOlLVAlNE 2,626,053

MOLDERS STATION SAND SCREEN Filed Aug. 5. 1947 35 J4 V ixiivr WW gmmmiummn Z2 1 224. E 1 j foam? 1. H614 mm:

Patented Jan, 20, .1953

MOLDERS STATION SAND SCREEN Robert L. Mcllvaine, Glencoe, 111., assignor, by

mesne assignments, to Herbert Simpson Corporation, Chicago, Ill., a corporation of Illinois Application August 5, 1947, SerialNo. 766,153

Claims.

This invention relates to improvements in sand molding apparatus and more particularly to improvements in a device for delivering granular material, such as sand, of varying textures to a molders station for use by the molder in preparing the mold.

In green sand molding, sand of definite physical characteristics, known as backing sand, is used to make up the greater part of the mold. This backing sand is lumpy in texture and sometimes contains a few pieces of foreign material such as shot iron or small pieces of nails. While this backing sand is satisfactory for the bulk of the mold, the portion of the mold at the joint between the cope and the drag and on either side of the pattern must be made of riddled sand, because at these points uniformity of ramming and venting is of great importance.

Riddled sand is backing sand that has been screened through a. sieve to break up and remove the lumps or any foreign material that is present. This sand is deposited at the joint in the mold and next to the pattern to a depth of from a fraction of an inch to several inches depending upon the size of the casting.

Backing sand may conveniently be mixed and prepared at a central work area and delivered to the molders station by a conveyor system. However, the preparation of riddled sand at a central station and delivery by a conveyor are not justified owing to the relatively small amount of this sand that is used. Heretofore, it has been the usual practice for each molder to keep a supply of sand in a small portable container near his molding machine. as a riddle, has a wire mesh or sieve bottom. When riddled sand is required the molder shakes the riddle over the mold and deposits finely divided or riddled sand thereon.

It is evident, therefore, that it would be a great convenience if the finely divided riddled sand were automatically delivered to the molders station in an adequate quantity at a point, such as an overhead chute, from which it could be quickly directed into the mold with a minimum of wasted energy.

Accordingly, it is an important object of the present invention to provide apparatus for conveying riddled sand to a position convenient to the molders station.

Another object is to provide an apparatus which is arranged to deliver backing sand and riddled sand independently of each other to the molders station.

A further object is to provide a device which This container, known is arranged to receive backing sand from a conveyor system and to automatically riddle a predetermined quantity of the backing sand and deliver it to a separate storage chamber for use by the molder.

According to the general features of this invention, there is provided an overhead bin arranged to receive backing sand from a conveyor, directing a portion of it to a backing sand dispensing chute and another portion to a screen ing device which automatically riddles a predetermined quantity of sand and delivers it to a riddled sand distributing chute.

An important feature of the present invention is the provision of a pivoting discharge gate arranged to be held in a closed position, a partially opened position for delivering riddled sand to the mold 01' a full open position for discharging backing sand to the mold.

Another feature resides in the provision of a control system which starts the automatic screening device when the discharge door is fully closed and stops it when a predetermined quantity of riddled sand has been delivered to the riddled sand discharge chute.

A further feature of this invention is the provision of an automatic screening device arranged to riddle backing sand as it passes down an inclined screen, delivering riddled sand at its lower end to the riddled sand discharge chute and unriddled sand and foreign matter to an overflow chute.

The novel features which I believe to be characteristic of my invention are set forth in the appended claims; My invention, however, both as to its manner of construction and method of operation, together with further objects and advantages thereof, may best be understood by reference to the followingdescription, taken in connection with the accompanying drawings, in which:

Figure 1 is a fragmentary side elevaticnal view. partly in section and partly broken away, of the sand handling and screening apparatus of the present invention.

Figure 2 is a fragmentary enlarged sectional view of the discharge chute of the apparatus of Fi 1.

Figure 3 is a fragmentary, vertical sectional view taken substantially on line IIIIII of Fig. 1,

and

Figure 4 is a diagrammatic illustration of the control apparatus of the present invention.

As shown on the drawings: In Fig. 1, reference numeral I0 designates a bin supported from a frame structure H and arranged to receive backing sand from a conveyor I2. A screening device I 3 receives sand from one chute I 4 of the bin I and automatically screens a definite amount of the sand and delivers it to a riddled sand discharge chute I5. A second chute I6 located in the bin I0, which will be referred to as the backing sand discharge chute, is arranged to support the chute I5, both chutes being closed by a pivotal gate I7 and depending above the molders station in convenient position for directing the sand from either chute into a flask I8 positioned on a molding machine I 9.

The bin I 0, which may be made of heavy sheet metal, comprises a pair of side plates 2I and 2Ia and a pair of end plates 22 and 22a, suitably secured together as by welding at their marginal portions. Each of the side plates 2| and 2 la has an inverted wedge-shaped cutout portion 23. A pair of closure plates 25 and 26 are disposed between the side plates 2| and Zia at the cutout portion 23, plate 25 coacting with the end plate 22 and the side plates 2I and 2m to form chute I4 while the closure plate 26 coacts with the end plate 22a and the side plates 2| and 2Ia to define chute I5.

The bin II] may be suitably supported from the upright frame structure II by angle bars 25 suitably secured, as by riveting, one on either side of the bin.

The conveyor system I2 comprises a belt 38 disposed over a drum 3|, rotatably mounted on upright members 33 and 34 which may conveniently be supported by the frame structure II. Backing sand, prepared at a central mixing area, is carried on the overhead belt past the bin iii which is suspended above the molders station. A chute 35, supported from the upright member 34 by means of a bracket 35, carries a rake 3'1 arranged to extend a fixed distance out over the surface of the belt in scrapin relation therewith. The rake 37 is disposed at an angle to the direction of travel of the sand on the belt so that the sand coming in contact with the rake will be directed off the belt and into the chute 35. The chute has a lower opening 5541 so disposed that sand leaving the chute 35 will be directed into both the backing sand discharge chute I6 and the chute I4 leading to the screening device I3.

An important feature of the present invention resides in the arrangement and operation of the screening device I3 which device may conveniently comprise an elongated trough AS, the enlarged box-like upper end of which is disposed directly under the chute It for receiving sand therefrom and the lower end of which overlies the riddled sand discharge chute I5. This trough 4B which may be made of sheet metal, is resiliently mounted on a suitable support structure 42 by means of a plurality of le members 43. The leg members 43 are secured at an angle to the top of the support structure 42 and are preferably made of a resilient material such as spring steel.

A screen 45 is disposed longitudinally of the trough 48, being removably secured at its side marginal portions by cap screws 46, Fig. 3, to angle members 61 which are welded to the side walls of the trough. The screen 45 is stretched across the trough at a level substantially half way between the top and bottom thereof. Thus, the screened or riddled sand will work its way through the screen-t0 a lower level of the trough for discharge into the riddled sand discharge chute I5 while the lumps and foreign matter will remain on the screen and work their way down to a chute 48 which is supported close to the lower end of the screen 45, as shown in Figs. 1 and 3. The chute 48 may lead to any suitable container for this unriddled sand.

The bed of the trough 49 and the screen 45 are inclined slightly downwardly toward the chute I5. A vibrating movement is imparted to the resiliently mounted trough by means of a vibrator mechanism such as the electric vibrator 50 comprising electromagnets 5I suitably connected to a source of alternating or interrupted current, as across terminals 52 and 53. When the trough is vibrated, the sand will be discharged from the lower end of the trough into the chute I5.

The flow of sand from the chutes I5 and It is controlled by a gate I! which is substantially a U-shaped sheet metal member having a curved bottom closure portion and is arranged for pivoting on either side of the bin Ill as at 55. A lever 56, which has one end within convenient reach of the molder, is pivotally mounted on the bin at 51 and carries a link 58 which is pivotally connected to both the gate I7 and the lever 55. As the molder swings the lever 58 counterclockwise about the point 51, the gate I I will be swung about its pivot point thus openin the chutes I5 and I6.

As the riddled sand leaves the chute I 5, it enters a guide trough 62, which is secured to the chute, as by welding, for directing the sand into the flask I8.

Thus, by manipulating the lever US, the molder may consecutively direct riddled sand from the chute I5 and then backing sand from the chute I6 into the flask I8. It is contemplated in this invention that the inertia of the gate I? pivoting at 55 is such that the gate will remain partially open in any position dictated by the swinging of the lever 56. Thus, after directing riddled sand into the flask, the gate will remain in the position shown in Fig. 2, while the molder manually distributes the riddled sand in the flask. Upon further opening of the gate, the backing will be directed into the flask.

The amount of sand that is riddled by the screening device I 3 is dependent upon the length of time that the vibrating apparatus to is operated. Since it is desirable that a predetermined quantity of riddled sand be stored in the discharge chute I5, control means is provided in the form of a switch 58, which may convenient- 1y be a suitable micro-switch and which is socured on the bin ID in a position for actuation by the gate I I as it is swung into closed position. A pressure actuated switch SI, which may be of any standard construction and arranged to be sensitive to the pressure of the sand in the chute, is mounted on the chute I5 at the desired level, having its pressure sensitive member projecting into the chute so as to be actuated by the sand only when the desired height of sand is reached.

In Fig. 4 is shown a diagrammatic sketch of the control system. Assume that the gate I! is open and the chute i5 is empty. To fill the chute 65, the gate I7 is closed, thereby closing the switch .ce which-is normally open. The vibrator 59 begins toactuate the screening device I3 and riddled sand .is delivered to the chute I5. When the sand has reached a predetermined height in the chute I5, the'switch 6i, which is normally closed, will be opened thus breaking the circuit and stopping the vibrator. Of course, when the gate I7 is opened, the switch 60 Will be opened by spring means in the switch and when the level of the sand in the chute recedes the switch 6| will be closed by spring action.

Thus, there is provided in the present invention means for automatically riddling sand and delivering the riddled sand in a predetermined quantity to a discharge chute convenient to the molders station. The fineness of the riddled sand may be controlled by varying the mesh of screen which is removably secured in a vibrating trough. There is also provided a pivotable gate by which either backing sand or riddled sand may be selectively directed to the molding machine.

It will, of course, be understood that various details of construction may be varied through a wide range without departing from the principles of this invention, and it is, therefore, not the purpose to limit the patent granted hereon otherwise than necessitated by the scope of the appended claims.

I claim as my invention:

1. A device for preparing sand for a mold comprising in combination a bin having first and second chutes, means for delivering sand to the first and second chutes of said bin, an auxiliary chute adjacent said second chute, screening means receiving sand from said first chute, said auxiliary chute being disposed below said screening means for receiving sand therefrom and a gate member swingable over said auxiliary chute and said second chute for controlling flow of sand therefrom.

2. A device for preparing sand for a mold comprising in combination a bin having first and second chutes, means for delivering sand to the first and second chutes of said bin, an auxiliary chute adjacent said second chute, screening means receiving sand from said first chute, said auxiliary chute being disposed below said screening means for receiving sand therefrom, a gate member swingable over said auxiliary chute and said second chute for controlling flow of sand therefrom, and control means for regulating the quantity of sand discharged into said auxiliary chute.

3. A device for preparing sand for a mold comprising in combination a bin having a discharge opening, means for delivering sand to said bin, screening means below said bin receiving sand from the discharge opening, a chute below said screening means receiving screened sand therefrom, a gate disposed for controlling flow of sand from said chute and means responsive to the closing of said gate to start operation of said 6 screening means, and means responsive to the height of sand in said chute for stopping the operation of said screening means.

4. In combination a bin having a first and second discharge opening, conveyor means for delivering sand to said bin, screening means in communication with said first discharge opening for receiving sand from said bin, a storage chamher in communication with said screening means and having a discharge opening, a control gate movable over said second discharge opening in said bin and said discharge opening in said storage chamber for selective control of discharge from said storage chamber and said bin.

5. A device for preparing sand for a mold comprising, in combination, a bin having first and second chutes, means for delivering sand to said first and said second chutes, an auxiliary chute adjacent said second chute, and screening means receiving sand from said first chute, said auxiliary chute being disposed below said screening means. forreceiving sand therefrom, said auxiliary chute and said second chute having adjacent discharge openings for discharge respectively of screened and unscreened sand, and unitary closure means movable to selectively close said auxiliary chute discharge opening and said second chute discharge opening for controlling flow of sand therefrom.

ROBERT L. McILVAINE.

REFERENCES CITED UNITED STATES PATENTS Number Name Date 433,166 Gandy July 29, 1890 535,429 Wehrer Mar. 12, 1895 681,378 Shoemaker et al. Aug. 27, 1901 935,216 Meiklejohn et al. Sept. 28, 1909 1,100,793 Stromberg June 23, 1914 1,123,385 Rose Jan. 5, 1915 1,205,431 Burns Nov. 21, 1916 1,286,881 Gray Dec. 3, 1918 1,397,906 Ruprecht Nov. 22, 1921 1,455,742 Bates May 15, 1923 1,489,938 Hale Apr. 8, 1924 1,746,766 Crandall Feb. 11, 1930 1,962,734 Dupre June 12, 1934 2,381,505 Lindholm Aug. 7, 1945 2,408,221 Michel Sept. 24, 1946 2,412,425 Rawson Dec. 10, 1946 OTHER REFERENCES Wendt, Foundry Work, pages 16-19, First Edition. 

